Yahoo! Pipes
I’ve had some fun working with Yahoo! Pipes recently. It’s a service that allows you to combine, sort, rename and generally manipulate (or mashup) data from a range of sources including spreadsheets, RSS feeds, JSON, web pages, Flickr and YouTube APIs etc and output it as you like. You can also set a pipe up to receive input from the user, so they can eg search or filter content in the pipe.
You don’t need to write any code; it’s a drag and drop interface. It probably helps to know some fundamentals of working with data, but it’s a really useful tool. I’ve used it recently, slightly mundanely, to slightly rename elements in a podcast feed and output it in Javascript-publishable JSON format (Show Radio) as well as combine a few e-learning feeds for including in one pane on my iGoogle page.
The interface is pretty intuitive and there are plenty of how-tos and a support forum. The main point when starting out seems to be to realise the service only updates output feeds every 30 minutes; eager new users need to know this to avoid disappointment when latest info doesn’t appear straight after publishing.